Gas turbines are widely used in industrial and commercial operations. As shown in FIG. 1, a typical gas turbine 10 includes an axial compressor 12 at the front, one or more combustors 14 around the middle, and a turbine 16 at the rear. The compressor 12 includes multiple stages of rotating blades and stationary vanes. Ambient air enters the compressor 12, and the rotating blades and stationary vanes progressively impart kinetic energy to the working fluid (air) to bring it to a highly energized state. The working fluid exits the compressor 12 and flows to the combustors 14 where it mixes with fuel 18 and ignites to generate combustion gases having a high temperature, pressure, and velocity. The combustion gases exit the combustors 14 and flow to the turbine 16 where they expand to produce work.
Gas turbines, like any other mechanical device, require periodic repairs and maintenance to ensure proper operation. As a general approach, previous experiences with the “fleet” of gas turbines, particularly comparable gas turbines of similar class or type, may be statistically analyzed to develop a fleet model that can project the anticipated wear and damage experienced by other gas turbines. Based on the fleet model, projections, repairs, and maintenance can be scheduled at optimum intervals that minimize the risk of both unplanned shutdowns to effect repairs and also unnecessary shutdowns to perform unnecessary preventive maintenance.
The actual performance of individual gas turbines, however, may vary from the fleet model. For example, individual gas turbines may have slight differences in configuration, manufacturing tolerances, and assembly that can result in different levels of wear and damage compared to the fleet model. In addition, the operational, repair, and maintenance histories that individual gas turbines actually experience may differ from the fleet average. For example, gas turbines operated in humid and corrosive environments may require more frequent repairs and maintenance to address issues associated with corrosion, pitting, and emissions compared to the fleet model. Conversely, other gas turbines that experience fewer startups and shutdown cycles may require less frequent shutdowns to perform preventive maintenance associated with cyclical stresses compared to the fleet model. In each example, adjustments to the fleet model based on the actual data associated with individual gas turbines will enhance the ability to optimally schedule repairs and maintenance.
Therefore, an improved system and method for monitoring the performance and operation of a gas turbine would be desirable.